<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
	<title></title>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
	<?php
		function congtru($x, $y){
			$tong = $x + $y;
			$hieu = $x - $y;
			$dapso = array($tong, $hieu);
			return $dapso;
		}

		$total = congtru(8,3);
		echo "Tổng số: {$total[0]}<br>";
		echo "Hiệu số: {$total[1]}<br>";

		list($tong, $hieu) = congtru(8,5);
		echo "Tổng số: {$tong}<br>";
		echo "Tổng số: {$hieu}<br>";
	?>
</body>
</html>